1. Field of the Invention This invention relates to a biochemical analysis apparatus and a method of controlling said, and a more particularly to controlling biochemical analysis apparatus in which a frameless dry chemical analysis film having a reagent layer containing a reagent whose optical density changes through a chemical reaction, a biochemical reaction, an immunoreaction or the like with a specific biochemical component contained in a sample liquid such as blood or urine is taken out from a cartridge, transferred to a sample liquid spotting position, applied with a sample liquid by spotting in the sample liquid spotting position, transferred to an incubator, inserted into the incubator and taken out from the incubator and at least one of these steps is effected with the film held by a suction means.
2. Description of the Prior Art
There has been put into practice a xe2x80x9cdry-to-the-touchxe2x80x9d chemical analysis film with which the content of a specific chemical component contained in a sample liquid, the activity thereof or the content of a solid component can be quantitatively analyzed by only spotting a droplet of the sample liquid on the film. One example of a day chemical analysis film is an integrated multi-layered chemical analysis film (sometimes referred to as xe2x80x9cmulti-layered chemical analysis elementxe2x80x9d) comprising a support sheet of organic polymer and at least one reagent layer which contains a reagent and is formed on the support sheet. A spreading layer is sometimes provided over the reagent layer. Further, a dry chemical analysis element which is formed of filter paper and has one or more layers has been proposed and partly put into practice.
When quantitatively analyzing the chemical components or the like contained in a sample liquid using such a dry chemical analysis film, a droplet of the sample liquid is typically spotted on the film (on the spreading layer when the film is provided with a spreading layer and on the reagent layer when the film is not provided with a spreading layer) and held at a constant temperature for a predetermined time (incubation) in an incubator so that a coloring reaction occurs. The optical density of the color formed by the coloring reaction is then optically measured. That is, a wavelength is pre-selected according to the combination of the component to be analyzed and the reagent contained in the reagent layer of the film measuring light containing this wavelength is then projected onto the film, and the optical density of the film is measured. Then the concentration or the activity of the component to be analyzed is determined on the basis of the optical density using a calibration curve which represents the relation between the concentration of the biochemical component and the optical density.
The integrated multi-layered chemical analysis film is generally in the form of a film chip of a predetermined shapes, e.g., spuare or rectangle. The film chip is sometimes provided with a frame of organic polymer and used in the form of a chemical analysis slide. The frame helps to flatten the film chip which is apt to curl or warp in a dry state, thereby facilitating automated handling of the chemical analysis film. However use of the chemical analysis slide is disadvantageous in that the chemical analysis slide is larger than the chemical analysis film chip by the size of the frame and accordingly parts of the biochemical analysis apparatus must be larger, which obstructs reduction in size of the biochemical analysis apparatus and at the same time results in reduction of the overall throughput capacity of the biochemical analysis apparatus. Thus, the use of the chemical analysis slides adds to the cost of measurement.
In a biochemical analysis apparatus we have proposed previously, the film chip is used without a frame (hereinafter referred to as xe2x80x9cframeless chemical analysis filmxe2x80x9d). A plurality of the frameless chemical analysis films are loaded in a cartridge and the cartridge is loaded in a chemical analysis film supplier for a biochemical analysis apparatus. The frameless chemical analysis films are taken out from the cartridge in the supplier one by one by use of a suction pad as disclosed, for instance, in our patent applications such as Japanese Patent Application No. 5(1993)-177056 and U.S. Pat. application Ser. No. 08/273,131, now U.S. Pat. No. 5,534,224.
Since the-frameless chemical analysis film is curled or warped into a roof tile-shape in the dry state, taking out the film by attracting it under a suction force by the suction pad as described above should be the best way of taking out the film from the cartridge without damaging the surface of the film.
In the biochemical analysis apparatus, the frameless chemical analysis film taken out from the cartridge is transferred to the spotting position and a sample liquid is spotted on the film. Thereafter the film is transferred to the incubator and inserted into a cell in the incubator. After a predetermined incubation, the optical density of the biochemical substance is measured, and the film is taken out from the cell and discarded in a predetermined discarding box. In many of these steps, a plurality of suction means, e.g., suction pads and horseshoe-like suction means, are used to hold the frameless chemical analysis film. The suction pads and the horseshoe-like suction means are disclosed in detail in the Japanese patent applications identified above and the like.
Since the suction means must surely hold the frameless chemical analysis film which is light in weight and small in thickness, it is necessary to constantly keep the suction force at an optimal level. However, the suction force can be easily changed by various causes, such as a clogin the suction pipe from dust, detects in the vacuum pump, valves, filters or the like, and/or cracking in the suction means etc.
Further, since many suction means are used in the biochemical analysis apparatus, it is difficult for the operator to constantly check the suction force of each suction means.
In view of the foregoing observations and description, the primary object of the present invention is to provide a method of controlling a biochemical analysis apparatus which can constantly watch the attracting state of the suction means.
Another object of the present invention is to provide a method of controlling a biochemical analysis apparatus which can inform the operator when the attracting state of the suction means is abnormal.
Still another object of the present invention is to provide a method of controlling a biochemical analysis apparatus which can quickly remove dust or the like when the attracting state of the suction means is abnormal due to dust, etc. Clogging the suction means.
In accordance with the present invention, there is provided a method of controlling a biochemical analysis apparatus in which a frameless dry chemical analysis film having a reagent layer formed on a support sheet is taken out from a cartridge, applied with a sample liquid, inserted into an incubator and taken out from the incubator, and at least a part of these steps and film transferring steps between these steps is effected with the film held by a suction means.
Furthermore, a change of pressure in the suction means is measured when the suction means attracts the film under a suction force, judging the attracting state of the suction means on the basis of the result of the measurement and controlling the part of the steps which is effected with the film held by the suction means on the basis of the judgment.
In one embodiment of the present invention, the attracting state of the suction means is indicated by a visual and/or acoustic means such as a monitor, a LED or a buzzer.
In another embodiment of the present invention, air is blown outside the suction means through the portion on which the suction means attracts the film.
In this embodiment, air may be blown at any timing. For example, air may be blown when an abnormality occurs or may be blown at regular intervals.
The term xe2x80x9cattracting state of the suction meansxe2x80x9d means the state of maintenance of the suction-means itself and the state of attraction of the suction means for the film.
In the method of the present invention, the change of pressure in the suction means (e.g., the suction pads and the horseshoe-like suction means used in the biochemical analysis apparatus) when the suction means attracts the frameless chemical analysis film under suction force.
The change of the pressure shows a peculiar pattern according to the attracting state of the suction means. For example, when the attracting force of the suction means is normal and the state of attraction of the suction means for the film is normal, the pressure in the suction means is lowered to a predetermined value within a predetermined time after initiation of attraction of the suction means for the film, and then kept at the predetermined pressure.
When a leak occurs in the vacuum pump or the vacuum line for the suction means, or the vacuum line clogs, the pressure in the suction means cannot be lowered to the predetermined value within the predetermined time after initiation of attraction of the suction means for the film. Further when the film is attracted to the suction means in a wrong position, the pressure in the suction means fluctuates after it is lowered to the predetermined pressure within the predetermined time.
Thus, the attracting state of the suction means can be known by monitoring the change of the pressure in the suction means, and the biochemical analysis apparatus can be properly controlled according to the attracting state of the suction means. For example, the succeeding steps of the biochemical analysis apparatus may be interrupted or the suction means may be cleaned before the succeeding step when the attracting state of the suction means is abnormal.
Further when the attracting state is indicated by a visual and/or acoustic means such as a monitor, a LED or a buzzer, the operator can instantly know that the attracting state of the suction means is abnormal and can quickly deal with the trouble.
Further, when air is blown outside the suction means through the portion on which the suction means attracts the film, dust or the like in the suction means can be blown out, whereby maintenance of the suction a means is facilitated.
It is preferred that air be blown not only when an abnormality occurs but also at regular intervals.